Apparatus for the production of fibrous tubing



F 1932- E. BEILHARTZ 1,854,168

APPARATUS FOR THE PRODUCTION OF FIBROUS TUBING Original Filed Sept. 16, 1930 1172 3070 ey p Patented Apr. 19, 1932 UNITED STATES PATENT. OFFICE v EH11 BEIIIHAIIEt'JJZ,v OF ZEHDENIOK, NEAR BERLIN, GERMANY, ASSIGNOR' TO FIRM GESELLSCHAIFT FUR ELEKTRISCHE ISOLIERUNGEN G. M. B. H., OF ZEHDENICK, NEAR BERLIN, GERMANY APPARATUS FOR THE PRODUCTION OF FIBROUS TUBING Original application filed September 16, 1930, Serial no. 482,350, and in Germany August 14, 1930. Divided and this application filed June 6, 1931. Serial No. 542,638.

The present invention relates to the pr oduction of fibrous tubing by means of bobbin or braiding machines, and it relatesparticularly to the production of such tubing as 1s {5 used for electrical insulation purposes. The tubing produced so far for these purposes with the aid of bobbin or braiding machlnes did not possess generally any persistence of form, but as a rule totally collapsed on leaving the bobbin or braiding machine. For

this reason it was ordinarily pressed flat be- ,tween special rollers for the purpose, of avoiding any distortions of the threads when storing or winding up the tubing. Prior to providing the tubing subsequently with the coating of lacquer made of oil varnish, nitrocellulose varnish and the like, for insulating purposes, the tubing required to be formed by special methods and widened, if desired, 2 thus causing it to assume its original cylindrical shape. 1 for the purpose of enabling the wires to be drawn through subsequently, but above all it was rendered necessary for the simple reason, that otherwise there was the risk of the walls of the tubing sticking together when applying the coating of varnish thereto. This special necessity of forming and widening of the tubing caused the latter 3 to be excessively shortened, and special difficulties in connection herewith and particularl when producing endless tubing, had to be faced and overcome, which has been attempted by special means more or less successfully. Nor could it be avoided in these circumstances that the tubing was subject to distortions which, in consideration of its subsequent application as an insulating tubing for wires and the like, was likely to exercise a detrimental and disturbing influence.

I now have found that contrary to all expectations it is possible to form immediately upon the bobbin or braiding machine hollow cylindrical tubing capable of permanently maintaining its shape, even when being stored or wound up. The production of tubing of such shape immediately upon the braiding or bobbin machine by correspondingly increasing the number of braids per unit of 50 length or the number of threads in proportion This was not only necessary to the number of bobbins used for producing the tubing has been described and claimed in the copending application Ser. No. 482,350 filed by Hermann Linstedt and myself, and of which the present application is a division.

The tubing thus produced by braiding possesses suiiicient strength in itself in order to maintain its hollow-cylindrical shape as well during the process of production as when being stored and during its further treatment (application of the coatings, drawing through of the wires and the like). The thickness of the yarn employed in this process exercises, it is true, a certain influence upon the persistence of form of the tubing produced, but this is in no way decisive. It is rather essential, as already pointed out that in relation to the cross section of the tubing the number of bobbins or the number of braidings and the angle of inclination of the braids, as well as the number of threads in relation to the number of bobbins employed is chosen correspondingly high.

For the purpose of producing the tubing in accordance with this process any kind of fibrous material adapted thereto, may be employed, i. e. not only cotton, but also synthetic fibre or synthetic threads, paper threads, asbestos threads and the like.

If, for the purpose of producing the tubing, one of the well-known braiding machines is made use of, in which the threads of the material are made to pass through a ring at the point of crossing, being braided at the same time, and a mandrel is provided over which the braiding and simultaneously the forming of the tubing is effected, it will, however, not be possible to attainethe desired result with security, because the' braided material will adhere to the mandrel, causing a backward or downward braiding to take place which will .ender the production of useful tubing a matter of impossibility or at least will prevent the production of a uniform tubing of equal cross section throughout.

I now have found, that it will be possible to avoid these drawbacks, if the interior mandrel of the machine is moved to and fro with great velocity duringthe braiding or the like and is made to be of special shape, preferably of conical shape. The stroke movement of the mandrel herein is suitably made very narrow or small, and the movement suitably is made to be so rapid, that these movements of the mandrel will be of a vibratory nature.

It is true, that braiding machines with movable mandrels are known in themselves. In the known case, however, the mandrel merely serves as a receiver or carrier for the braid and is, moreover, moved to and fro only slowly nor is it of the preferred conical shape at the point of braiding, and it is therefore obvious, that with the aid of this known device, which is intended to serve quite a different purpose, it will not be possible to obviate the drawbacks previously referred to.

- For the purpose of illustrating one suitable form of braiding machine is shown in the drawings which also shows the new mandrel arrangement. A

Fig. 1 represents the main part of the ma chine in a side view and partly in section;

Fig. 2 shows a detail View of the new arrangement for the mandrel, partly in section on a greater scale; and

Fig. 3 represents a part of the prepared tubing.

The braiding machine shown in Fig. 1 generally is of known construction. L is the braiding machine proper having the bobbins M of which only four are shown in the drawings forsake of clearness and which are to be revolved in the usual manner. The threads a, Z), c, d coming from these bobbins are passed through the ring E. The threads to be braided are made to meet in the usual manner above the bored part F. Through the central bore of the part F the braiding mandrel A is made to pass, being tapered at the braiding point, i. e. above the part F, viz. at A. Above the conical part A of the mandrel the ring E has been placed, through which the braiding or tubing G, produced at the point of crossing of the threads, i. e. at D, is passing.

The braiding mandrel A is now made to describe a most rapid vibratory motion. This may be effected by any desired means, e'. g. by causing the lower end of the mandrel A to rest, by means of a roll H, upon a rapidly driven cam B which, on revolving, causes the mandrel A to be raised. By means of the spring C, resting upon the shoulder J of the mandrel A and being in engagement with an abutment K of the housing N of the mandrel A, this mandrel is pressed downwards again and caused to maintain its contact with the cam surface of the part B, if the dead weight of the mandrel alone should prove insufficient for that (purpose. The cam B is fastened on a spindle This spindle may be driven by a pulley R arranged thereon, the revolving movement being transmitted thereto by means of a strap Q, from a driving pulley P.

Owing to the rapid and short to and fro motion of the mandrel A it will be attained,

1,sa4,1es

. that the tubing G in being formed is moved on in an upward direction and that an adhering or a downward braiding of the tubing at the point of braiding will be avoided with absolute certainty. In addition thereto, the conical shape of the mandrel end A at the point of braiding will prevent a amming or sticking of the material.

It is not absolutely necessary that the mandrel is, as shown, tapering to its upper end; it will, under certain circumstances, be sufficient, if the tapering takes place only at the point of braiding and that from that point onward, the mandrel assumes again its cylindrical shape.

The transport of the braided tubing G gliding down from the mandrel A may be eflected in any desired manner. Either, it may be drawn off from the tapering part A of the mandrel A by pulling means or elements or else a device may be made use of, with the aid of which a more or less stepwise transport of the tubing thus produced has been rendered possible. For instance, in conjunction with the device described, an appliance may be employed which renders it possible, to move the tubing on stepwise over the mandrel by means of rollers coming in engagement with the outside of the tubin in combination with movable stop-rings. buch an arrangement here is easily to be employed, because the mandrel is perfectly straight and any bent parts are avoided. The vibratory motion of the mandrel does not prevent the employment of such an arrangement.

Part of the tubing manufactured by the described process is shown in Fig. 3. It will be seen therefrom, that it is of perfectly hollow cylindrical form and that it differs from known fibrous tubings of this kind by the very dense braiding of the threads or sets of threads.

Having now particularly described and ascertained the nature of my said invention, what I claim is 1. A machine for the production of braided fibrous tubing, particularly such for electro-technical purposes, said machine having a number of revolvable bobbins arranged in a circle on a revolvable disc, a ring in the axis of said disc above said bobbins, the threads coming from said bobbins passing said disc, a mandrel passing said disc beyond and in the interior of said threads coming from said bobbins, said interior mandrel being arranged to be moved to and fro in the direction of its axis, and means for moving said mandrel to and fro with such a velocity that a rapid shaking movement is obtained. 1

2. A machine for the production of braided fibrous tubing, particularly such for electrotechnical purposes, said machine having a number of revolvable bobbins arranged in a circle on a revolvable disc, a ring in the axis of said disc above said bobbins, the threads coming from said bobbins passing said disc,

' "a mandrel passing said disc beyond and in interior mandrel the interior of said threads coming from said bobbins, said interior mandrel being arranged to be moved to and fro in the direction of its axis, and means for moving said mandrel to and fro with such a velocity that a rapid shaking movement is obtained, said mandrel being tapered at the point of braiding.

3. A machinefor the production of braided fibrous'tubing, particularly such for electro-technical purposes, said machine having a number of revolvable bobblns arranged in a clrcle on a revolvable d1sc, a ring 1n the axis of said disc above said bobbins, thethreads coming from 'said bobbins passing said disc, a mandrel passing said disc beyond and in the interior of said threads coming from said bobbins, said interior mandrel being arranged to be moved to and fro in the direction of-its axis, and means for moving said mandrel to and fro with great velocity, means for making the. stroke of said movement to be so short, that a vibratory motion is produced.

4. A machine for the production of braided fibrous tubing, particularly such for elect-rotechnical purposes, said machine having a number of revolvable bobbins arranged in a circle on a :revolvable disc, a ring in the axis of said disc above said bobbins, the threads coming from said bobbins passing said disc, a mandrel passing said disc beyond and in the interior of said threads coming from said bobbins, a cam for moving said arallel to itself in one direction and a sprlng for returning it in the opposite direction, means for turning said cam with great velocity, said cam having only a small eccentricity.

In testimony whereof my hand.

, EMIL BEILHARTZ.

I have hereunto-set 

